According to the development of electronic devices having a more sophisticated function and a smaller size, a circuit board has been required to be capable of having electronic components mounted thereto at a high density.
The circuit board disclosed in Patent Document 1 includes a print wiring board having plurality wiring layers and an electronic component mounted to an inner layer out of the wiring layers. This electronic component is, e.g. a chip component, such as a chip capacitor. Thus, a part of such an electronic component to be mounted on an outer layer of a print wiring board is accommodated in the board, electronic components can be mounted on the print wiring board at a high density.
Electronic components accommodated in a print wiring board are often limited to be a passive component, such as a capacitor and a resistor. Active components, such as semiconductor devices can be mounted at a limited density on the entire circuit board. In order to allow the active components to be accommodated in the print wiring board, complicated processes, such as a process for making a cavity for accommodating the active component and a process for sealing the active component, are required.    Patent Document 1: JP2007-214230A